When a guide wire assembly is placed into a vascular, biliary, or urogenital lumen, the operator has to maintain it in place by holding the proximal end still. When a catheter or related endoluminal device is brought over the assembly, the assembly's distal end may start moving, because the relatively rigid catheter influences the geometry of the floppy guide wire, especially in tortuous arteries. The catheter will tend to straighten the guide wire assembly, thus creating a pull force on the guide wire tip, which causes an undesired movement. When the distal end of the assembly moves back in a proximal direction, it may slip out of the target artery, and if this happens, it will be necessary to pull the devices back to repeat the procedure. This is often the case if the guide wire makes a bend before the most flexible tip enters the target artery.
Previous attempts at developing a medical line anchoring system include using a simply-structured device that permits a portion of a catheter tube or similar medical article to be easily anchored to a patient, desirably without the use of tape, needles or suturing. In one exemplary device, shown and described in U.S. Pat. No. 6,447,485 to Bierman, a unitary retainer desirably includes a base connected to a cover by way of a flexible hinge. The retainer is attached to a flexible anchor pad including an adhesive bottom surface, which can be attached to the patient's skin. Such is an example of anchoring outside the body. In other approaches, elongated members that can lock themselves in place in a body site can be used. For example, in U.S. Pat. No. 6,544,262 to Fleischman discloses electrodes with an expandable tip that anchors the electrode to a body lumen or related tissue. In another method, the wire is held in place is by means of an inflatable balloon near the distal end, as shown in for example U.S. Pat. No. 6,595,989 to Schaer. Likewise, in U.S. Pat. No. 6,254,550 to McNamara et al, a preformed wire guide is shown, which can anchor itself in a side artery (for example a renal artery), because the wire has been treated to obtain a strong bend at the entrance of the side artery. At the site of this bend the wire can anchor itself, because at the given location the target artery makes a strong angle with the main access artery (aorta). Therefore the wire will hang with its bent section on the entrance of the side artery. In U.S. Pat. No. 4,884,579 to Engelson, anchoring is achieved by giving the distal section of the guide wire a less slippery surface. While such an approach increases the grip, care must be exercised during insertion when minimal friction is required, as too strong of a grip may additionally damage the vessel wall.
Guide wire assemblies with a steerable tip are well-known in the art. Some types have a shapeable tip that can be bent to a desired angle before insertion. While the angle enables the operator to find a way into side arteries, its relatively fixed nature means that once in the body, the angle can not be changed. Therefore it is better to have a remote control, where the curvature of the tip is steered by proximal actuation. In one example, hollow guide wires include a floppy tip, where a pre-bent wire can be advanced into the floppy region to change the curvature. For example, in U.S. Pat. No. 6,599,254 to Winters, a hollow guide wire with a tension wire attached to the floppy tip at an eccentric place is disclosed. If the operator pulls the tension wire relative to the guide wire, the tip will bend. The curvature can be adjusted, dependent on the pull force. In another example, U.S. Pat. No. 5,741,429 to Donadio III et al gives a hollow guide wire with a series of slots made in the tube wall at the place where more flexibility is desired. Manufacturing processes for the apparatus, including slotted hypotube, for use as a catheter, a guide wire, a catheter sheath for use with catheter introducers or a drug infusion catheter or guide wire are disclosed. The manufacturing process includes creating a pattern of slots or apertures in a flexible metallic tubular member, by processes including but not limited to, electrostatic discharge machining (EDM), chemical milling, ablation and laser cutting. These slots or apertures may be cut completely or partially through the wall of the flexible metallic tubular member. Other slotted configurations are also possible. For example, in U.S. Patent Application Publication 20030069522, a slotted medical device is described, with a plurality of pairs of slots cut into the body to make it more flexible in bending while maintaining adequate torsional stiffness.
In all cases, the actuation is controlled from the proximal end. This is done with some additional tool or actuation means, which will in general have a different geometry and typically a larger diameter than the guide wire assembly itself. Such an actuation means attached to the proximal end section makes it impossible to slide the catheter over this proximal end. Therefore, the actuation means has to be uncoupled to bring the catheter over this proximal end. This is the case for over the wire catheters as well as for rapid exchange catheters. This is disadvantageous, because in placing the catheter over the guide wire, the operator can not hold the distal section of the guide wire assembly in a fixed, anchored position.
Accordingly, there exists a need for an endoluminal device that is capable of being manipulated at a proximal end while having its distal end situated in, steered through and anchorable in a body lumen. Further, there exists a need for an endoluminal device that is in a readily-activated state to facilitate shape changes capable of producing enhanced levels of steerability and anchorability.